Consensus Mechanisms

Question 1

PoW – how is consensus leader chosen?

Answer 1

First miner to hash a block header below target difficulty wins.

Question 2

PoW – biggest downside?

Answer 2

High energy consumption and pooling → potential 51 % centralisation.

Question 3

PoS – how is block proposer selected?

Answer 3

Pseudo‑random selection weighted by each validator’s staked coins.

Question 4

PoS – main security incentive?

Answer 4

Misbehaving validator’s stake can be slashed (burned).

Question 5

DPoS – core mechanism?

Answer 5

Token holders elect a small set of delegates who alternate block production.

Question 6

PBFT – fault tolerance rule?

Answer 6

Consensus holds if <33 % of nodes are faulty/malicious.

Question 7

FBA (e.g., Stellar) – unique feature?

Answer 7

Nodes rely on overlapping quorum slices, not the whole network, for agreement.

Question 8

PoW vs PoS – resource expended?

Answer 8

PoW burns electricity; PoS locks capital.

Question 9

Typical confirmation time: PoW vs PoS?

Answer 9

PoW uses probabilistic ~1 hour (6 blocks); PoS can finalise in minutes (checkpoint).

Question 10

Name two PoS‑specific attack vectors.

Answer 10

Nothing‑at‑stake; Long‑range attack.